You'll Be Mine I'll Be Yours
by Outsiders Obsessor
Summary: Margaret and Gilthunder held a love for each other during the ten years they were cursed, but they were never able to experience the full potential of their love. With Dreyfus and Hendrickson being exposed as the true traitors, the two can begin to act on their feelings of attraction. Marthunder one-shots for each letter of the alphabet! (Will contain more characters than listed!)


**You'll Be Mine; I'll Be Yours**

 _Chapter One: At Your Service_

 **Disclaimer: I do not own any canon characters. Also, I have watched all of the episodes of the anime, but I have just now started to read the mangas with my younger sister. Therefore, I apologize if any of the information is wrong, but I wrote this because Margaret and Gilthunder become some of my favorite characters through the series. (Even though I didn't like Gilthunder until about episode 18 or 19. Sorry, Gil!) Without further ado, onto the story!**

The first official time Gilthunder says those three little words to Margaret, they are both ten years old.

"At your service," a ten-year-old Gilthunder whispers as he bows to Margaret, his heart beating a million miles a minute.

"Arise, Gilthunder, and pledge yourself to Princess Margaret as her loyal protector," King Baltra announces in a booming voice as he holds his oldest daughter's hand before gently pulling Margaret more towards Gilthunder.

Gilthunder quickly completes the task Baltra has asked of him, the young lad rising from the floor before looking Margaret in her stunning brown eyes. Almost as if attracted to one another by sheer gravity, Gilthunder stumbles forward as Margaret practically glides across the small space between them. A quick pause passes before Gilthunder begins speaking to the eldest daughter of King Baltra, in training to be the future Queen of her kingdom.

Brown eyes meet blue, and Gilthunder must swallow a lump in his throat as Margaret looks expectantly at him.

"Ma—I mean, Lady Margaret," young Gilthunder starts off, almost slipping up and calling the heir to the throne by the name he calls her during their unsupervised plays in the courtyard with Veronica and Elizabeth nearby.

 _"_ _No need for such repulsive formalities out here, Gil," Margaret would reprimand her best friend and playmate until Gilthunder eventually began to call her just Margaret._

It certainly is a good thing that Gilthunder caught what could have been a massive slip of the tongue before the one word alone came out of his mouth. As daughter to the King and son of the Grand Master, respectively, more formality and overall polish is expected from both Margaret and Gilthunder. Just a one word slip such as the one narrowly avoided could have gotten Gilthunder and Margaret in serious trouble with their fathers.

 _"_ _It is very unbefitting of a woman as powerful and generous as you, your mother, or sisters to be referred to without the title of Lady or Your Highness," Baltra would explain to young Margaret at either the beginning or ending of each of the eldest princess' daily lessons._

Little did King Baltra know that Princess Margaret would roll her eyes at such constant formality from those she adored, such as Gilthunder, Sir Zaratras, and Sir Meliodas. Such behavior would prompt laughter from Veronica, especially when Margaret would rant to her younger sister by three years that Zaratras and Meliodas had earned those titles through valor, honor, and prestige.

 _"_ _And being heir to the throne of Liones is not honorable, prestigious, and showing valor?" Veronica would always tease, and it would make Margaret's head spin._

Frankly, Margaret didn't know if she believed being born into power was a legitimate reason for being treated with forced formalities.

When Gilthunder begins to speak, Margaret is snapped out of her own thoughts and returns to her current ceremony in which Gilthunder will pledge himself to uphold his job as loyal protector of honor and justice while also being pledged to protect and serve Princess Margaret. Being the first princess and heir to the throne of Liones means that Margaret must always have a guard stationed outside her bedchambers or following her nearly anywhere she goes. The Holy Knights, particularly the Seven Deadly Sins, do a fantastic job of protecting King Baltra and his three daughters, taking to the task with ease. While Sir Meliodas seemed more connected to Elizabeth in particular, he makes sure to treat Margaret and Veronica with the same amount of respect and care he gives the youngest princess of Liones.

"Lady Margaret," Gilthunder begins again, his young voice wavering slightly at the thought of speaking in front of this many people of such high rank and esteem.

The young Holy Knight in training can only hope his face does not betray the true extent of his fear.

"I promise to be at your service whenever you should beckon me to your side or chambers. Your life shall come before my own, Lady Margaret, and I will never allow anything to harm you or threaten your life. You shall always be in my heart and mind-" Gilthunder barely manages to squeak out, his cheeks turning a brilliant shade of crimson as he realizes he has let his inner thoughts come out of his mouth.

Gilthunder has _always_ loved Margaret, ever since their first encounter as children younger than they are currently. Though they are now ten-years-old, Gilthunder and Margaret have not allowed their bond to dissolve; if anything, their relationship has strengthened over the years. And yet, the pure, genuine smile on Margaret's face right now is enough to startle Gilthunder into starting to fall in love with Princess Margaret all over again. Maybe he should seriously start to consider taking Sir Meliodas and Sir Ban up on their offers to teach him how to court a special lady, as his father did not wish to discuss such a subject due to losing Gilthunder's mother. Yes, perhaps the lessons will help him not continue to be a nervous, stuttering mess around the eldest Princess of Liones.

"Do you accept Sir Gilthunder's pledge to you, Lady Margaret?" Baltra inquires, moving a sword to rest on Gilthunder's right shoulder- preparing to dub him a knight in training- before the King of Liones looks his eldest daughter in her soft brown eyes.

Margaret needs to accept Gilthunder's pledge and request in order for the son of the Grand Master to be accepted as a Holy Knight in training and become her personal protector that would attend certain meetings and ceremonies with her as they both continue to mature and grow. For the next five years, however, their bond would be allowed to grow, and they would always be shadowed by a Holy Knight, usually one of the Seven Deadly Sins, with the exception of during their unsupervised playtime in the courtyard with Veronica, Elizabeth, and usually Howzer and Griamore as well. Oh, how the two long for that time together.

"I accept the pledge of Sir Gilthunder and also accept him as my loyal protector," Margaret regally answers, her chin pointed forward and the smallest of smiles tugging at her lips as she looks Gilthunder in his striking blue eyes.

Gilthunder's smile could not be wider than it is right now. Frankly, the young son of the Grand Master of Liones tunes out most of the rest of the ceremony, focusing his attention on King Baltra only when Margaret's name or his own name come into the speech. The rest of the time Gilthunder spends on trying not to blush as Lady Margaret either tosses a smile his way or fixes her gaze upon him as he starts to fidget at his seemingly permanent position. The pointing and kissy faces from Sir Meliodas, Sir Ban, and Lady Diane, respectfully, are certainly not helping Gilthunder contain his emotion and retain composure.

At fifteen-years-old, the words are uttered once more for a more interesting reason than they have been these past five years. After all, Margaret has been going through classes and training to help her become ready to take over as Queen of Liones when the time is right. As for Gilthunder, the young man has been stuck in training course after training course with Howzer and Griamore in order to help them become Holy Knights strong enough and worthy enough to defeat the rebel Seven Deadly Sins who have been charged with the murder of Grand Master Zaratras. Gilthunder has dealt with his father's death as best as can be expected, but he suddenly starts to feel quite off even months after he knew he had gotten to the point of acceptance of his father's death. Unfortunately, Gilthunder has had to train so hard to make sure he could become a Holy Knight and honor his father's memory and name. Gilthunder has had to train so hard to defeat the Seven Deadly Sins who had killed his father. He has to-

"Gil," comes Margaret's melodic, calming voice, causing Gilthunder to spin around and face her.

"Lady Margaret!" Gilthunder gasps, bowing to her with one arm crossed over his chest. "What may I do for you today, my lady?" the pink-haired young man inquires, pausing to wipe a line of sweat from his brow.

"Gil, how many times must I ask you to call me Margaret?" the crown princess questions, thoroughly disappointed that Gilthunder has regained his almost constant formality.

And, to think, they had once been so close… Now they hardly get the time to spend contented days sitting and talking to one another on the castle's lowest wall.

"At least once more, as always, Lady Margaret," Gilthunder whispers, and he can't help but feel like the words he uttered were not his own.

Could it be that someone is controlling him? Would that explain his recent behavior and desires?

 _"_ _Don't be ridiculous, Gilthunder! Surely such a thing doesn't exist," the young Holy Knight chides himself within his own thoughts._

And yet Gilthunder does not believe those thoughts are his own, either. He and Margaret had a conversation about this once when meeting up for their required presence at a banquet. However, the memory was quickly wiped from both of their heads.

There is one force on Earth that keeps Gilthunder vaguely aware that he is under either a spell or curse. His love for Margaret remains, dripping into every fiber of his being and pouring into his heart every day and every time Margaret catches his eyes. They may be cursed or under a spell, but by his father's honor, Gilthunder swears one day he will be able to express his deepest feelings to Margaret without fear of someone overhearing him or punishing the two of them for such pure love and limitless amounts of adoration. No spell on Earth could keep him away from Margaret, and the two try the hardest they can to sneak in time together.

"Gil, there is a festival in town that I rather wish to go and attend," Margaret begins to state, hope and excitement shining in her eyes. "However, none of the Holy Knights within the castle walls will take me, on account of them deeming the festival as too dangerous," Margaret pauses, and here she smiles, almost as if trying to hint at an invitation to Gilthunder.

Gilthunder's heart flutters wildly in his chest, and the curse he is under seems to disappear long enough for him to speak his own mind.

"Lady Margaret, I would be happy to attend the festival with you," the young Holy Knight smiles, the wind blowing through his pink-colored hair. "You need only ask, as I cannot give you commands as a Holy Knight unless the commands will save your life," Gilthunder continues, a grin creeping over his face as he looks into Margaret's eyes, blue eyes piercing into brown eyes.

"Sir Gilthunder, will you attend tonight's festival with me as my friend instead of my personal guard for just one night?" Margaret sweetly smiles, closing the small gap between them, leaning her face closer to Gilthunder's as they exchange smiles and silent conversations.

"I would be honored to attend the festival as your friend, Margaret," Gilthunder beams, heart beating a mile a minute with his blue eyes shining like a sapphire. "At your service," he bows like the gentleman his late father raised him as before Gilthunder then offers his arm out to Margaret.

"Oh, Gil," Margaret laughs, looping her own arm over Gilthunder's before they both begin to slip away from the castle towards the festival grounds.

They are going to leave early so as not to divert any suspicions upon themselves. No one has noticed neither Margaret nor Gilthunder are present for their current lessons, and neither the princess nor her Holy Knight in training want to be caught breaking the rules, especially not with each other. That would be grounds for trouble for each teenager, not to mention that Grand Masters Hendrickson and Dreyfus could request Gilthunder be removed from his duty as Margaret's loyal protector. No, the stakes are too high, so being careless or being caught cannot happen, lest all their hard work to see each other against the curse would be ruined. Margaret and Gilthunder leave the castle grounds smiling and holding hands, both teenagers feeling love for one another despite the curse constantly gnawing at their hearts and minds.

When Meliodas, Dragon Sin of Wrath and Captain of the Seven Deadly Sins, breaks the curse, Margaret has just turned twenty-one, and Gilthunder is at the stable age of twenty. Ten years of their lives are practically missing. Ten years of their lives have been taken from them. Stolen are the days when Margaret and Gilthunder should have had time to forge a stronger bond as first Princess of Liones and Holy Knight in training, respectfully. When Baltra knighted Gilthunder, the King of Liones expected his eldest daughter and the son of Grand Master Zaratras would have five years to spend with each other as a knight serving his lady. At the time, Baltra would have made Meliodas, Ban, or any of the other Seven Deadly Sins watch over his Margaret as Gilthunder trained to become the sole protector of Margaret. Others would fight to defend Margaret, Veronica, and Elizabeth, keeping them alive and out of harm's way- namely the Seven Deadly Sins, Zaratras, Howzer, and Griamore- but Gilthunder was to become her main line of defense and protection. Ideally, this training with adult supervision would last five years for Gilthunder and Margaret before they would be allowed off the castle grounds by themselves at age fifteen. Baltra's plan only succeeded for a month before Zaratras was murdered and the Sins were exiled and marked as traitors, pushing Gilthunder's education and freedom- along with Margaret's freedom- to the back of everyone's mind. Instead, the young son of the deceased Grand Master Zaratras was fated to become his uncle Dreyfus' prize pupil, someone even Grand Master Hendrickson was proud of.

During their time under the curse keeping them apart and naïve, Margaret and Gilthunder witnessed many tragedies and heart-breaking scenes. However, during the time the curse affected them, neither the Princess of Liones nor Holy Knight could confide in anyone about their nightmares. Howzer and Griamore would have made exceptional confidants for Gilthunder, much like Veronica and Elizabeth could have for Margaret. And yet, Margaret and Gilthunder kept their mouths firmly shut about their nightmares due to the mind control aspect of the curse that cleansed dreams- whether good or bad- from their heads like clock-work. One night after the curse is broken and both Dreyfus and Hendrickson have been "defeated", Gilthunder is walking past Margaret's private bedchambers when he hears it. He can hear Margaret's frightened screams and cries from down the hall. Taking off in the fastest sprint he has ever managed in his life, Gilthunder quickly reaches the door to Margaret's bedchamber.

"Margaret!" Gilthunder calls from outside Margaret's chambers. "Margaret, are you okay?" the Holy Knight inquires, putting his hand on the door handle while preparing to open the door to Margaret's room.

Usually, a guard is forever present outside of Margaret's room as well as Veronica's and Elizabeth's, but with all the re-building Liones needs, many of the guards have been temporary construction workers to the castle. The screams continuing to come from Margaret's lip seem to do nothing except frighten Gilthunder even more than usual for Margaret's safety. So, with his heart hammering in his chest, Gilthunder throws open the door to Margaret's bedchambers, expecting the worst but hoping for the best.

The sight that greets his eyes is not at all what Gilthunder expected. _At all._ Margaret is burrowed under her blankets, clutching at the duvet with pale knuckles as she tosses and turns within her king-sized bed. Gilthunder is across the room in a second, preparing to climb into Margaret's bed and pull her trembling form close to his chest to help her fight the demons in her head. Such a behavior would usually be defined as scandalous, but due to the fact that Gilthunder is Margaret's Holy Knight protector- and the man she loves- there are no extremely strict rules King Baltra could impose. Not that Baltra could really make legislation or catch Gilthunder due to Merlin and Arthur taking the sick King of Liones to Camelot to be cured. Gilthunder climbs into the bed beside Margaret to try and comfort her. The Diamond-ranking Holy Knight wastes no time pulling the covers away from Margaret's face, not wanting her to have a lack of air, as the crown princess' breaths are already coming out in ragged gasps.

"Margaret," Gilthunder gently says, his voice no higher than a whisper as he moves to wrap his arms around the trembling purple-haired princess. "Margaret, can you hear me?" he inquires next, pink hair flopping onto his forehead and beginning to slightly cover his vibrant blue eyes.

He really needs to ask either Howzer or Margaret to cut his hair before too much time passes…

Margaret's soft, brown eyes open suddenly and Gilthunder lets out a quick sigh of relief, knowing the woman he loves is safe.

"Gil?" Margaret barely manages to rasp out, her voice dry from the amount of screaming she did prior to waking up.

"Yes, Margaret. It is I," Gilthunder responds, his cheeks flushing a light pink when Margaret rests one hand on either side of his face.

"Gil!" Margaret happily says, taking her hands off Gilthunder's face in favor of wrapping her arms around his neck as she sits up in the bed. "It is not that I am displeased with your presence in my bedchamber. But, why are you here at this late hour, Gilthunder?" the heir to the throne of Liones questions, smiling briefly when she feels Gilthunder's arms wrap tightly around her, keeping her safe and out of danger.

Margaret instantly folds herself into Gilthunder's embrace, pressing her back against his chest and allowing her hands to wrap around her Holy Knight's bulging biceps. Fortunately for Margaret, Gilthunder has removed his gauntlets for the night, so her touch is applied to Gil's soft, warm skin in opposed to the usual rough, impenetrable armor Gilthunder normally wears when Margaret sees him.

"I am merely at your service, my love," Gilthunder speaks, his voice betraying his complete sense of love he feels towards Margaret.

At the end of that sentence, Gilthunder drops a kiss to Margaret's temple, enjoying the flood of scent from her hair into his nose in the process.

"You were screaming, and I was so frightened something terrible happened to you, Margaret," the Holy Knight admits, tightening his grip around her waist and upper body.

They sit in silence for an unspecified amount of time, Margaret's breathing becoming normal once more.

When Margaret speaks once more, her voice is no longer shaking, and she turns her body to where she can now look Gilthunder in his eyes.

"I dreamt you were gone, Gil," she admits, unwrapping her hands from Gilthunder's face and instead laces their fingers together. "In some versions, you were dead; in others you were banished and forbidden from seeing me ever again," Margaret admits the first stage of her nightmare that came almost every night before she had broken out of the prison cell under the castle. "And—And in other versions, Gilthunder, you married that cruel mage Vivian!" the eldest princess reveals, jealousy and rage shining in her otherwise soft, gentle eyes.

"Margaret, listen to me," Gilthunder gently commands, using one of his strong hands to softly tilt Margaret's chin upwards.

Their eyes lock onto one another's, and Gilthunder presses a kiss to Margaret's forehead before continuing.

"I will never leave you. I devote my love and my heart to you every day. Besides, I would never love someone so cruel and deceitful," Gil smirks, and Margaret cannot help but laugh.

"Truly, you are noble and a worthy suitor," Margaret grins, pressing her lips to Gilthunder's cheek. "Stay to protect me this night," she gently commands.

"Margaret, wouldn't doing that simply cause a-"

"A scandal? Gil, don't be so afraid. Father is in Camelot, and Elizabeth has made it clear that she and Sir Meliodas have been sharing a bed at that tavern of his. Please. Stay and chase the nightmares away. You won't get in trouble…"

"Then, in that case, I am at your service, Margaret," Gilthunder grins, lying down before wrapping Margaret in his strong embrace.

 **Author's Note: And there it is! My first ever story about Gilthunder and Margaret! I am quite pleased with how it turned out, especially since I wrote it during my free time I had at school when it started back on August 7** **th** **. Long story short, they stuck me in a study hall I didn't want, and thus, this story was born. I plan on this story eventually being twenty-six chapters long, one for each letter of the alphabet. That being said, I need help from you, my dear readers. Right now, I only have about half of the alphabet accounted for! Therefore, I will gladly take all suggestions, prompts, etc., as long as they are kept in the T rating! There will be no content more extreme or graphic than the show's content, keep that in mind. The rating on this story is T simply because I am not sure how much violence or mention of violence will be mentioned in later chapters. Thanks in advance for your help! I do have B covered, but after that, not many of the letters are a definite outline. I hope everyone enjoyed the first chapter, and I look forward to hearing your thoughts for later chapters! Hope to hear from you soon, my dear readers, and until next time! Have a nice day, afternoon, or night!**


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